Magpul CTR stock stuck on buffer tube....Need to Remove.

Last night I attempted to install my new CTR stock on my Stag lower. I checked to make sure (website and measuring) that I order the correct milspec CTR stock for my Stag milspec BT. Well, I was so excited to install the CTR stock that I did not read the instructions about pulling down the metal posts on each side of the locking pin in order to install the CTR stock.
I got the stock about 1/4 of the way on the buffer tube and now it's stuck.

I have since tried to pull down themetal posts on each side of the locking pin, and I'm able to do so, but the stock is not budging.
Could you guys provide me with some assistance?

Inspection FAIL on my part. Sure enough, I have a commercial tube. It was on too tight, but I was able to get it off. So, on that note.....would anyone like to purchase a fully functional CTR milspec stock?

Johnny5.56. The tubes are basically the same except the comercial have a slightly larger diameter and the transition to the locking rail is slightly rounded verses the sharp transition on the mil spec tube. Also the Mil spec tube should have lathe cut threads verses the cheaper roll cut threads on comercial tubes. The tubes have the same threads though and it would probably be cheaper to just get yourself a mil spec tube and replace your comercial one.

Johnny5.56. The tubes are basically the same except the comercial have a slightly larger diameter and the transition to the locking rail is slightly rounded verses the sharp transition on the mil spec tube. Also the Mil spec tube should have lathe cut threads verses the cheaper roll cut threads on comercial tubes. The tubes have the same threads though and it would probably be cheaper to just get yourself a mil spec tube and replace your comercial one.

Thanks for the info. Which milspec tube do you recommend at a decent price? Can I use the same spring and buffer?